1. Field of the Invention
The present invention relates to access control mechanisms, and more particularly to an interactively authorizing access control method.
2. Description of Related Art
An access control mechanism can be used to record access information of objects such as access time, restrict access authority for objects and set certain access time for objects. The access control mechanism can be a gate control system of a building, a vehicle access control system of a factory or a parking lot, or a commodity theft preventing system of a marketplace. The objects to be controlled can be vehicles, personnel, commodities or other items.
To describe the access control method in detail, we use an example of a access control system of a parking lot. In such an access control system, the validity of permits are identified for determining whether the objects are allowed to access or not and the moving status of vehicles at the gate or at other certain areas are monitored by monitors. Currently, the permits can be automatically identified by devices or manually identified by guards. However, both these methods require vehicles to stay at a certain zone, which not only slows down the access speed of vehicles, brings inconvenience to drivers, but also often causes jams. Meanwhile, since the permit can be copied easily, it increases the risks of vehicle thefts. Although such risks can be decreased by stricter examination of vehicles, it causes the problems such as much slower access speed of vehicles and so on.
In recent years, permits integrated with radio frequency identification (RFID) technology have been developed for vehicle access controlling. Such permits include personal information such as RFID tags for identification. Although the identification method with the help of the RFID technology can increase the access speed, prevent faked permits and reduce the labor cost, the problem of unauthorized use of a permit still exists. That is, as long as a permit can be identified, the corresponding vehicle is allowed to pass no matter who is the driver, which decreases the safety of vehicles in the parking lot. For example, a permit disposed near the windshield of a vehicle can be easily stolen or used by children without permission of parents. Thus, big safety problems exist in such an access control system.
For example, U.S. Pat. No. 6,427,913 and U.S. publication No. 20050040232 disclose application of the RFID technology in parking lots for vehicle access control. According to those inventions, the code information of the RFID tag on a vehicle is first read by an RFID reader and then processed by a computer or a CPU for identifying. If the code information is identified, the corresponding vehicle is allowed to pass. In both inventions, there exists the abovementioned problem of unauthorized use of the permit. In addition, since identification needs to be performed at certain zones, it causes slow pass speed and brings inconvenient vehicle driving. From the cost-effective viewpoint, both these inventions are almost same as the automatic card identification method.
U.S. patent publication No. 20050046584 discloses an access control mechanism, wherein the wireless communication technology is used to control a movable device (object). According to the invention, the object can be prevented from leaving home, provided that someone is at home and notices the alarm signal. Such a condition limits the application of the present invention. Further, if the object is used by other authorized users while the authorizer does not change the authorizing status timely, a false alarm can be triggered, thereby decreasing reliability of the control mechanism.
In view of the above prior art, there is a need to develop an access control mechanism which can prevent unauthorized use of permits and improve the pass speed.